In the prior art, to improve transmission reliability, a hybrid automatic repeat request (HARQ) technology is used for data transmission, that is, a receive end needs to feed back, to a transmit end, indication information used to indicate whether data transmitted by the transmit end is successfully received. Specifically, if reception fails, the receive end feeds back a negative-acknowledgment (NACK) message to the transmit end. Correspondingly, after receiving the NACK message, the transmit end may retransmit data according to a specified HARQ time sequence relationship. In this case, because both a feedback of the receive end and retransmission of the transmit end cause a transmission delay, there is a relatively great transmission delay for data transmission performed using the HARQ technology. A future communications system, for example, a system using uplink grant-free (Grant Free) transmission, usually requires relatively low signaling overheads and a relatively short transmission delay. However, the HARQ technology does not meet a transmission delay requirement of the future communications system.